Photoredox Cleavage of a C_sp3-C_sp3 Bond in Aromatic Hydrocarbons

Functionalizingmolecules through the selective cleavage of carbon-carbonbonds is an attractive approach in synthetic chemistry. Despite recentadvances in both transition-metal catalysis and radical chemistry,the selective cleavage of inert C-sp3-C-sp3 bonds in hydrocarbon feedstocks remains challenging. Examples reportedin the literature typically involve substrates containing redox functionalgroups or highly strained molecules. In this article, we present astraightforward protocol for the cleavage and functionalization ofC(sp3)-C-sp3 bonds in alkylbenzenes usingphotoredox catalysis. Our method employs two distinct bond scissionpathways. For substrates with tertiary benzylic substituents, a carbocation-coupledelectron transfer mechanism is prevalent. For substrates with primaryor secondary benzylic substituents, a triple single-electron oxidationcascade is applicable. Our strategy offers a practical means of cleavinginert C-sp3-C-sp3 bonds in molecules withoutany heteroatoms, resulting in primary, secondary, tertiary, and benzylicradical species.